Researchers studied 101 people who had a newer type of weight loss surgery called one anastomosis gastric bypass (OAGB). Two years after surgery, patients lost significant weight, their blood sugar levels improved dramatically, and their cholesterol dropped. Most importantly, very few patients developed nutritional deficiencies—problems where the body doesn’t get enough important vitamins and minerals. This suggests OAGB could be a safe and effective option for people struggling with severe obesity and related health problems like diabetes.

The Quick Take

  • What they studied: How well a newer weight loss surgery called OAGB works for helping people lose weight and improve their health problems, and whether it causes nutritional deficiencies
  • Who participated: 101 people with an average age of 45 years who were severely overweight (average BMI of 47, which is considered obese). The study followed them for up to 2 years after surgery
  • Key finding: Two years after surgery, patients’ weight dropped from an average BMI of 47.6 to 29.4 (a healthy range), blood sugar levels improved by about 18%, and cholesterol dropped significantly. Very few patients developed vitamin or mineral deficiencies—less than 9% for any single nutrient
  • What it means for you: If you’re considering weight loss surgery, OAGB may be an effective option that produces substantial weight loss and improves obesity-related diseases like diabetes, with a low risk of developing nutritional problems. However, this was a single-center study, so results should be confirmed with larger research

The Research Details

This was a single-center study where researchers followed 101 patients who had OAGB surgery between 2014 and 2019. They measured patients’ weight, blood sugar control, cholesterol levels, and nutritional markers (vitamins and minerals) before surgery and then at 6 months, 12 months, and 24 months after surgery. They compared the before and after measurements to see what changed.

The researchers used statistical tests to determine whether the changes they observed were real and significant, not just random variation. They set a standard threshold (called a p-value of 0.05) to decide if results were statistically meaningful. This means they were 95% confident in their findings.

This research approach is important because it provides real-world evidence of how OAGB performs in actual clinical practice over a 2-year period. By measuring multiple important health markers—not just weight, but also blood sugar, cholesterol, and nutritional status—the researchers could determine whether the surgery improves overall health. The 2-year follow-up period is long enough to see sustained benefits and identify potential nutritional problems that might develop after surgery.

This study has some strengths: it followed patients for 2 years, measured multiple important health outcomes, and used proper statistical analysis. However, readers should know that this was a single-center study (one hospital), which means results might not apply everywhere. The study didn’t have a comparison group of people who didn’t have surgery, so we can’t say for certain that the improvements were caused by surgery alone. The sample size of 101 is moderate—larger studies would provide more confidence in the results.

What the Results Show

The surgery produced dramatic weight loss. Patients’ BMI (a measure of weight relative to height) dropped from an average of 47.6 before surgery to 29.4 two years later—moving from the obese category into the normal weight range. This represents an average weight loss of about 50-60 pounds for most patients.

Blood sugar control improved significantly. Patients’ HbA1c (a measure of average blood sugar over 3 months) dropped from 6.7% to 5.5%, which is a substantial improvement. Even more impressive, the number of diabetes medications patients needed dropped from an average of 1.6 drugs per person to only 0.3 drugs—meaning many patients either eliminated their diabetes medications or needed far fewer.

Cholesterol levels also improved. LDL cholesterol (the ‘bad’ cholesterol) dropped from 3.2 to 2.05 mmol/L, which reduces heart disease risk. These improvements were consistent throughout the 2-year follow-up period, with the greatest benefits seen at the 24-month mark.

The nutritional deficiency rates were remarkably low. At 24 months, only 8.9% of patients had zinc deficiency, 4% had ferritin (iron storage) deficiency, 5.9% had folate deficiency, 0% had vitamin B12 deficiency, and 3% had vitamin D deficiency. These rates are much lower than what’s typically seen with other weight loss surgeries, suggesting OAGB may be gentler on nutritional status. The fact that no patients developed B12 deficiency is particularly notable, as this is a common problem after many weight loss surgeries.

OAGB is a relatively newer surgery compared to more established procedures like gastric bypass or gastric sleeve. This study adds important evidence that OAGB produces weight loss and health improvements comparable to or better than older procedures, while potentially causing fewer nutritional deficiencies. The low deficiency rates are particularly significant because nutritional problems are a major concern with weight loss surgery. This research suggests OAGB might be a safer alternative to traditional bypass surgeries.

This study has several limitations readers should understand. First, it only included 101 patients from one hospital, so results might not apply to all populations or settings. Second, there was no control group—patients who didn’t have surgery—so we can’t be 100% certain the improvements were caused by surgery rather than other lifestyle changes. Third, the study only followed patients for 2 years; longer-term effects beyond 2 years are unknown. Fourth, the study didn’t track whether patients made diet or exercise changes after surgery, which could have contributed to results. Finally, the study didn’t measure all possible nutritional deficiencies, only specific ones.

The Bottom Line

For people with severe obesity (BMI over 40) and related health problems like type 2 diabetes or high cholesterol, OAGB appears to be an effective surgical option that produces substantial weight loss and improves these conditions with relatively low risk of nutritional deficiencies (moderate confidence level). However, surgery should only be considered after trying other weight loss methods first, and patients should work with a healthcare team experienced in weight loss surgery. All weight loss surgery patients need lifelong nutritional monitoring and supplementation to prevent deficiencies.

This research is most relevant for people with severe obesity (BMI over 40) who have tried diet and exercise without success and have obesity-related health problems. It’s also important for surgeons and doctors who recommend weight loss surgery, as it provides evidence that OAGB is an effective option. People considering any weight loss surgery should discuss OAGB with their surgical team. This research is less relevant for people with mild to moderate weight problems who can lose weight through lifestyle changes alone.

Based on this study, most weight loss occurs in the first 6-12 months after surgery, with continued improvement through 24 months. Blood sugar improvements often happen quickly—sometimes within weeks—as patients lose weight and eat less. However, reaching maximum weight loss and health benefits typically takes 18-24 months. Nutritional deficiencies, if they develop, usually appear gradually over months to years, which is why lifelong monitoring is important.

Want to Apply This Research?

  • Track weekly weight, monthly blood sugar readings (if diabetic), and quarterly nutritional marker labs (B12, vitamin D, iron, folate, zinc). Set reminders for vitamin supplementation and medical appointments to monitor nutritional status
  • Users considering or recovering from OAGB can use the app to log daily protein intake (critical after surgery), track vitamin/mineral supplementation compliance, record hunger and fullness levels, and monitor portion sizes. Set daily goals for protein (typically 60-80g) and water intake (64+ ounces)
  • Create a long-term dashboard showing weight trends over months, blood sugar improvements, medication changes, and nutritional lab results. Set quarterly reminders for blood work and annual comprehensive nutritional assessments. Track adherence to vitamin supplementation as a key health metric

This research describes results from a single-center study of 101 patients and should not be considered a substitute for personalized medical advice. Weight loss surgery is a serious procedure with potential risks and benefits that vary by individual. Anyone considering OAGB or any weight loss surgery should consult with a qualified bariatric surgeon and their primary care doctor to discuss whether surgery is appropriate for their specific situation. This study does not replace the need for comprehensive pre-operative evaluation, informed consent discussions, and lifelong medical follow-up after surgery. Results from this study may not apply to all patients or settings. Always work with a healthcare team experienced in weight loss surgery.